Copolyamides containing caprolactam, lauriclactam and 11-aminoundecanoic acid

ABSTRACT

The invention relates to copolyamides containing caprolactam, lauriclactam and 11-amino-undecanoic acid, useful as heat sealing agents.

United States Patent [191 Raabe et al.

[ COPOLYAMIDES CONTAINING CAPROLACTAM, LAURICLACTAM AND ll-AMINOUNDECANOIC ACID [75] Inventors: Fritz Raabe, Bonn; Eduard de Jong,

Bonn-Beuel, both of Germany [73] Assignee: Plate Bonn Gesellschaft mit beschrankter Haftung, Bonn, Germany 22 Filed: July 31,1973

21 Appl. No.: 384,371

[30] Foreign Application Priority Data May 12, 1973 Germany 2324160 [52] U.S. Cl. 260/78 L; 117/161 P; 156/283; 156/307; 156/331; 161/227; 260/33.4 R; 260/78 A; 260/78 S May 13,1975

Primary Examiner-Lucille M. Phynes Attorney, Agent, or Firm-Donald D. Jeffery [57] ABSTRACT The invention relates to copolyamides containing caprolactam, lauriclactam and 1 l-amino-undecanoic acid, useful as heat sealing agents.

12 Claims, No Drawings COPOLYAMIDES CONTAINING CAPROLACTUM,

LAURICLACTAM AND ll-AMINOUNDECANOIC ACID This invention relates to copolyamides containing caprolactam, lauriclactam and l laminoundecanoic acid together with further polyamide-forming components as basic units, to a process for producing these copolyamides and to their use for heat-sealing.

BACKGROUND OF THE INVENTION Copolyamides of the basic units caprolactam, lauriclactam and l l-aminoundecanoic acid are known from DOS 1,595,591. In melt form, these ternary polyamides show high bond strength which is used in the textile industry for heat-sealing fabrics. In addition to high bond strength, these copolyamides show high resistance to solvents of the kind used for dry-cleaning textiles, and to the washing temperatures of up to about 80C normally encountered in the textile industry. Unfortunately, this resistance is largely governed by a high content of lauriclactam and/or 1 l-aminoundecanoic acid. Although the resistance of the copolyamides to washing at elevated temperatures increases with increasing content of these basic units, their melting temperature is also increased with the result that conventional copolyamides cannot be used for heat-sealing temperature-sensitive substrates such as leather, temperature sensitive natural and/or synthetic materials, non-woven fabrics, felts, tufted fabrics and the like. Substances melting below about 115, below 110 or even below 105C, are required for heat-sealing temperaturesensitive substrates of this kind.

THE INVENTION HOOC-(CH M-COOH in which n is the number 4, 7, 8, or 11, the basic units being incorporated in the copolymer by polymerisation in the following proportions:

20-40% by weight 20-35% by weight -35% by weight caprolactam lauriclactam l laminoundecanoic acid hexamethylene diamine salt of the acid of formula (I) 15-40% by weight The invention also relates to a process for producing copolyamides containing caprolactam, lauriclactam and 1 l-aminoundecanoic acid as basic units, distinguished by the fact that the aforementioned basic units and, as additional basic unit, a hexamethylene diamine salt of an aliphatic dicarboxylic acid, corresponding to the formula (I) in which n is 4, 7, 8, 10 or 11, are

20-40% by weight 20-35% by weight 15-35% by weight 15-40% by weight caprolactam lauriclactam I l-aminoundccanoic acid hexamethylene diamine salt of the acid of formula (I) by methods known per se.

The copolyamides defined above are used for heatsealing. Surprisingly, they have an extremely low melting point of below 110C, generally below 100C and, in some cases, even below C. Despite these low melting points, they show extremely high bond strength after heat-sealing at elevated temperature and. on the other hand, a high resistance to chemical cleaning agents, i.e. solvents and cleaning agents of the kind added to aqueous cleaning solutions. Accordingly. substrates heat-sealed with the copolyamides according to the invention show high resistance to water-containing cleaning agents, even at elevated washing temperatures.

Accordingly. the copolyamides according to the invention can be used with advantage for heat-sealing temperature-sensitive substrates.

Copolyamides of the kind whose basic units are incorporated in the copolymer in the following proportions:

25-35% by weight 30% by weight 18-257: by weight 15-30% by weight caprolactam lauriclactam l l-aminoundecanoic acid hcaxamethylene diamine salt of the acid of formula (I) 30% by weight 30% by weight 20% by weight 20% by weight caprolactam lauriclactam l l-aminoundccan0ic acid hexamethylene diamine salt of the acid of formula (I) The acids of general formula (I) have the following names:

11 4, adipic acid 11 7,azelaic acid n 8,sebacic acid )1 l0,dodecane dicarboxylic acid it l l,brassylic acid.

The acids of formula (I) in which n is 4, 7, 8 or 10 are particularly preferred for the purposes of the invention, acids in which n is 7 or 8 being particularly preferred because they are readily available commercial products and lead to copolyamides which can be used with particular advantage for heat-sealing.

According to the invention, the copolyamides are produced by methods known per se. As in the production of C12-polyamide from lauriclactam, temperatures of from about 280 to 300C, preferably of about 290C, and pressures of from about 10 to 50 atms, preferably from 15 to 30 atms, are generally used. Polymerisation is continued for several hours under these conditions and is preferably followed by aftercondensation for a few hours, preferably for about 1 to 3 hours, at 250 to 300C. The catalysts, chain terminators and/or other additives and the process conditions normally used for the polymerisation of lauriclactam are employed. More particularly, polymerisation is best carried out in the absence of air, i.e. in an inert gas atmosphere. The copolyamides according to the invention are preferably used for heat-sealing in the form of fine powders which are applied to the substrates to be bonded. A suitable viscosity of the copolyamide where it is used for the production of films is best in the range from about 1.4 to 1.5. This number denotes the solution viscosity of a 0.5 percent solution of the copolyamide in m-cresol at 25C.

The copolyamides used in accordance with the invention can contain other additives, for example dyes, in the usual way.

The copolyamides used in accordance with the invention are copolymers which are formed during the polymerisation of a mixture of the polyamide formers. The basic units are condensed into the polymer chain in statistical distribution. The surprising effects described are not obtained in cases where the polyamide formers are polymerised separately from and then melted together with the polyamides.

The copolyamides according to the invention can also have small quantities of other polyamide formers condensed into them.

For reasons of ready accessibility and satisfactory reproducibility of production to form copolyamides with uniform properties, it is generally not advisable to add further polyamide formers.

It is possible by means of the copolyamides according to the invention to bond substrates of many different kinds, particularly temperature-sensitive substrates to substrates of the same or different type. A copolyamide according to the invention is preferably introduced in the form of powder between the surfaces to be bonded. The copolyamide can of course also be used in the other forms, for example films, filaments or chopped filaments. The substrates are then pressed at elevated temperature. The pressing temperature is governed primarily by the temperature-sensitivity of the substrate. Since the copolyamides according to the invention develop outstanding bond strength even at very low sealing temperatures of, for example, from about 100 to 130C or up to 150C in dependence upon their melting range, it is possible to apply extremely low sealing temperatures. Cooling to room temperature is accompanied by hardening so that the bonded substrates are firmly united. There is no need for drying or evaporation of solvents.

The copolyamides according to the invention in the form of powders can be applied to a substrate to be bonded, for example by the powder coating machines normally used in the coating industry. ln this connection, it is also possible to coat only selected areas of the substrate surface with the copolyamide powder according to the invention. Examples of substrates to be bonded include textiles of natural materials and/or synthetic materials such as wool, silk, cotton and polyesters, polyamides and the like. Other temperaturesensitive substrates such as leather, plastics films and the like, can also be heat sealed using the copolyamides according to the invention.

DESCRIPTION OF PREFERRED EMBODIMENTS EXAMPLE 1 300 parts by weight of caprolactam, 200 parts by weight of 1 l-aminoundecanoic acid, 300 parts by weight of lauriclactam, 200 parts by weight of AH-salt (adipic acid hexamethylene diamine salt) and 12 parts by weight of adipic acid as polymerisation-degree regulator, are weighed into an autoclave equipped with stirring mechanism, a gas inlet and a gas outlet. The atmospheric oxygen present inside the autoclave is removed by repeated rinsing under pressure with purified nitrogen.

The reaction mixture is heated to 290C and the increasing pressure inside the autoclave limited to 25-30 atms by correspondingly setting the valve. The reaction mixture is stirred for 3 hours under these conditions.

The pressure is then reduced to normal pressure over a period of 2 hours.

The reaction mixture is then aftercondensed with stirring for 2 hours in the absence of pressure under a gentle stream of nitrogen.

On completion of the pressure-free aftercondensation phase, the temperature is lowered to 160l80C and the melt spun through a nozzle in the form of a monofil by means of a gear pump, cooled and granulated.

The resulting granulates have a melting range of from about to C, as measured on a KOFLER heatingstage microscope.

EXAMPLE 2 EXAMPLE 3 A copolyamide is prepared from the following components in the same way as described in Example 1: 250 parts by weight of caprolactam, 250 parts by weight of ll-aminoundecanoic acid, 250 parts by weight of lauric-lactam, 250 parts by weight of the salt of azelaic acid and hexamethylene diamine, 12 parts by weight of adipic acid. A copolyamide with a melting range of from about 84 to 88C is obtained.

EXAMPLE 4 The following monomer combination: 350 parts by weight of caprolactam, 200 parts by weight of 11- aminoundecanoic acid, 300 parts by weight of lauriclactam, 150 parts by weight of 6,12-salt and 12 parts by weight of adipic acid, gives a copolyamide with a melting range of 95 to 105C under the same polycondensation conditions asin Example 1.

EXAMPLE 5 A copolyamide with a melting range of 90 to C is obtained from the following components under the same polycondensation conditions as in Example 1: 300 parts by weight of caprolactam, 300 parts by weight of ll-aminoundecanoic acid, 200 parts by weight of lauriclactam, 200 parts by weight of 6,13-salt,

12 parts by weight of adipic acid.

amino-undecanoic acid, 25 ercent b wei ht of lauri- EXAMPLES 6 to 21 clactam, 25 percent by weight of a elaic acid hexa- Copolyamides were prepared from the starting commethylene diamine salt and 2 percent by weight of azeponents specified in Table 1 below in accordance with laic acid as polymerisation-degree regulator. A transthe procedure described in Example 1. The following 5 parent polyamide melting at 80 to 90C, as measured abbreviations were used: on a KOFLER heating-stage microscope, and having a melt index at 130C of 22, as measured in accordance with D1N 53,735, is obtained.

6 f f"t For comparison, a ternary copolyamide is prepared 11 llammoundccanolc acid 12 lauriclactam from the followmg constituents: 34 percent by weight 6,6 AH-sa1t(adipic acid hcxamcthylcnc diztminc f caprolactam 33 percent b i h f 1 1.

'1t 6,9 heiinrethykne diaminc amluic acid n ammoundecanotc acid, 33 percent by weight of launglg j g fiyl gif i 2 31 I, clactam and 1.5 percent by weight of azelaic acid as zg g g fine ammo Mr polymerisation degree regulator. A copolyamide melt- 6,13 hexamethylcne diaminc brass ylic acid salt ing at 1 10 to l 15C and having a melt index of 22, as measured in accordance with DIN 53,735, is obtained. The melting temperatures of the copolyamides 0b- The polyamides were each ground while cooling and tained are also shown in Table 1. separated by sifting into a fraction of 0 to 200 mm.

In the individual Examples, the quantities in which The two powder fractions were applied to a conventhe basic units are used can generally be varied by 0 tional interlining material in an ll-mesh pattern in an about i 3 percent or at least by 1.5 percent without adamount of 16: 1 g per in by means of a powder pointversely affecting the properties of the resulting ing machine of the kind normally used in the coating copolyamides to any appreciable extent. industry.

Table 1 EX- Monomer composition Melting range C 7o mple 6 35 35 10 100 105 7 35 20 30 15 103 108 8 3O 30 20 20 98 104 1 30 20 30 2O 90 95 9 40 20 15 105 110 10 25 25 25 25 95 100 1 l 20 25 25 83 89 3 25 25 25 25 84 88 12 30 2O 30 2O 88 95 13 30 15 2O 14 35 35 2O 10 100- 108 15 35 20 30 15 97 107 16 30 20 30 2O 90- 17 30 25 25 20 82- 90 18 3O 30 2O 20 9O 95 19 25 25 25 25 85 90 2 20 25 25 30 86- 91 20 3O 20 30 2O 95 21 35 20 30 15 95 4 35 20 3O 15 95 105 5 30 3O 2O 20 90 100 COMPARISON TEST The coated interlinings thus obtained were ironed with a polyester/cotton fabric under a constant pres- In companso" test the bond Strength of a sure of 350 p/cm in an electrically heated ironing press polyamide according to the lfl is comparfid i 50 of the kind commonly used in the garment industry, that of copolyamlde comammg y the baslc both the plate temperature and the contact time being caprolactam, ll-aminoundecanoic acid and lauriclaci d mm The delamination strengths of 2.5 cm wide laminate A copolyamide is prepared as described in Example strips were measured with a tension tester. 1 from the following monomer constituents: 25 percent 55 The delamination strengths (p/2.5 cm) specified in by weight of caprolactam, 25 percent by weight of 1 1- Table 2 were measured:

Table 2 Contact Plate temperature of the ironing time press (C) (seconds) 300 400 500 700 1000 900 900 Invention 6 100 200 400 300 300 Comparison 400 500 800 1100 1000 1100 1600 Invention 10 1 200 300 400 500 500 Comparison It can be seen from the Table that extremely good adhesion is obtained even at very low plate temperatures of the ironing press, i.e. at very low sealing temperatures of 110 and 120C, whereas no adhesion is obtained with the conventional copolyamide at these sealing temperatures. The conventional copolyamide only produces film adhesion at higher sealing temperatures.

What is claimed is:

l. A solid copolyamide consisting essentially of recurring units of caprolactam, lauriclactam, l laminoundecanoic acid and a hexamethylene diamine salt of an aliphatic dicarboxylic acid correspondingto the formula HOOC-(CH ),,COOH

in which n is 4, 7, 8, 10 or 11, wherein said units are incorporated in the copolyamide in the following proportions:

caprolactam lauriclactam l l-aminoundecanoic acid hexamethylenc diamine salt of the acid formula (I) 20-40% by weight 20-35% by weight 15-35% by weight 15-40% by weight.

'2. The copolyamide according to claim 1, wherein said units are incorporated in the copolyamide in the following proportions:

25-35% byweight about 30% by weight l825% by weight caprolactam' lauriclactam l l-aminoundecanoic acid hexamethylene diamine salt of the acid fonnula (I) 15-30% by weight.

3. The copolyamide according to claim 1, wherein said units are incorporated in the copolyamide in the following proportions:

caprolactam about 30% by weight lauriclactam [-l about 30% by weight I l-aminoundecanoic acid about 20% by weight hexamethylcne diamine salt 5 of the acid of formula (I) about 20% by weight.

4. The copolymide according to claim 1 wherein n in formula (I) is 4, 7, 8, or l0.

5. The copolyamide according to claim 4 wherein n in formula (I) is 7 or 8.

6. A process for producing powdery copolyamides consisting essentially of recurring units of caprolactam, lauriclactam ll-aminoundecanoic acid, and a hexamethylene diamine salt of an aliphatic dicarboxylic acid corresponding to the formula HOOC(CH ),,COOH

in which n is 4, 7, 8, 10 or 1 l comprising polymerizing said units under pressure at elevated temperature in the following quantitative proportions:

caprolactam lauriclactam l l-aminoundecanoic acid hexamethylene diamine salt of the acid formula (I) 2040% by weight 20-35% by weight 15-35% by weight 15-40% by weight 7. The process according to claim 6, wherein said units are polymerized in the following quantitative proportions:

2535% by weight about 30% by weight 18-25% by weight caprolactam lauriclactam l l-aminoundecanoic acid hexamethylene diaminesalt of the acid of formula (I) 15-30% by weight,

8. The process according to claim 6, wherein said units are polymerized in the following quantitative proportions:

caprolactam lauriclactam l l-aminoundecanoic acid hexamethylene diamine salt of the acid of formula (I) about 30% by weight about 30% by weight about 20% by weight 20% by weight.

9. The process according to claim 6, wherein n in formula (I) is 4, 7, 8 or 10.

- 10. The process according to claim 9 wherein n in formula (I) is 7 or 8. I

ll. Theprocess according to claim 6, wherein polymerization is carried out at a temperature of about 280 to 300C under a pressure of from about 10 to 50 atms.

12. The process according to claim 6, wherein aftercondensation is carried out for l to 3 hours at about 250 to 300C. 

1. A SOLID COPOLYAMIDE CONSISTING ESENTIALLY OF RECURRING UNITS OF CAPROLACTAM, LAURICLACTAM, 11 -AMINOUNDECANOIC ACID AND A HEXAMETHYLENE DIAMINE SALT OF AN ALIPHATIC DICARBOXYLIC ACID CORRESPONDING TO THE FORMULA HOOC-(CH2)N-COOH
 2. The copolyamide according to claim 1, wherein said units are incorporated in the copolyamide in the following proportions:
 3. The copolyamide according to claim 1, wherein said units are incorporated in the copolyamide in the following proportions:
 4. The copolymide according to claim 1 wherein n in formula (I) is 4, 7, 8, or
 10. 5. The copolyamide according to claim 4 wherein n in formula (I) is 7 or
 8. 6. A process for producing powdery copolyamides consisting essentially of recurring units of caprolactam, lauriclactam 11-aminoundecanoic acid, and a hexamethylene diamine salt of an aliphatic dicarboxylic acid corresponding to the formula HOOC-(CH2)n-COOH (I) in which n is 4, 7, 8, 10 or 11, comprising polymerizing said units under pressure at elevated temperature in the following quantitative proportions:
 7. The process according to claim 6, wherein said units are polymerized in the following quantitative proportions:
 8. The process according to claim 6, wherein said units are polymerized in the following quantitative proportions:
 9. The process according to claim 6, wherein n in formula (I) is 4, 7, 8 or
 10. 10. The process according to claim 9 wherein n in formula (I) is 7 or
 8. 11. The process according to claim 6, wherein polymerization is carried out at a temperature of about 280* to 300*C under a pressure of from about 10 to 50 atms.
 12. The process according to claim 6, wherein after-condensation is carried out for 1 to 3 hours at about 250* to 300*C. 